Orientation changes and associated lifetimes are analysed in terms
of first passage time and escape from metastable states [1]}. The distribution of lifetimes is anticipated to be Poissonian
as expected from a jump process controlled by an activation
“energy”. In a simplified one-dimensional version of potential \(\cal V\) 
[1]}, if the well is deep enough, within a parabolic
approximation the mean escape time, the average time necessary to go from a well to another, is given by
\(\tau /\tau _0=\frac{2\pi }{\sqrt{\mathcal {V}_{\rm w}^{\prime \prime }\,|\mathcal {V}_{\rm s}^{\prime \prime }|}}\exp \left(2\frac{\mathcal {V}_{\rm s}-\mathcal {V}_{\rm w}}{\alpha ^2}\right)\,,\) 
